To find News Transcripts, actually copies of scripts used on radio or TV, go to NexisLexis Academic and click on "Search by Content Type. Then under "News" select "Broadcast Transcipts."
Next type your search term in the search box and click "Search."
Once you get results you can narrow down by clicking on "News Transcripts"
Then you may view them all or choose to select only transcripts from a particular network, such as, CNN which has 82 transcripts in the above example